1. Field of the Invention
The present invention relates to a machine for processing printing material sheets. The machine has a signal generator for position monitoring and a sheet delivery, which includes a first conveying device for leading sheet ends and a second conveying device for trailing sheet ends.
In a machine of this type, each printing material sheet is held fixedly during transport at its leading sheet end by means of the first conveying device and, at the same time, at its trailing sheet end by means of the second conveying device. The conveying devices can be, for example, chain conveyors.
German published patent application DE 42 18 421 A1 and corresponding U.S. Pat. No. 5,431,386 describe a printing press having a sheet delivery, whose chain conveyors are driven synchronously by a separate drive. The separate drive is controlled via a signal generator which is probably configured as a rotary encoder and whose location of installation is not described in greater detail in the above-mentioned document.
It is known to those of skill in the pertinent art that printing units of printing presses are equipped with rotary encoders.
2. Summary of the Invention
It is accordingly an object of the invention to provide a machine for processing printing material sheets which overcomes the above-mentioned disadvantages of the heretofore-known devices and methods of this general type and which is enabled to ensure particularly high monitoring accuracy of the signal generator.
With the foregoing and other objects in view there is provided, in accordance with the invention, a sheet-processing machine for processing printing material sheets having leading sheet ends and trailing sheet ends, the machine comprising:
a sheet delivery having a first conveying device for the leading sheet ends and a second conveying device for the trailing sheet ends; and
a signal generator for position monitoring disposed in said sheet delivery.
In other words, the machine according to the invention for processing printing material sheets has a signal generator for position monitoring, and it has a sheet delivery with a first conveying device for leading sheet ends and a second conveying device for trailing sheet ends. The machine is distinguished by the fact that the signal generator is disposed in the sheet delivery.
This results in the advantage that the unavoidable play between the sheet delivery and the rest of the machine has no influence on the accuracy of the monitoring performed by way of the signal generator. In the case of a design of the machine as a printing press with a printing unit and the sheet delivery, for example, the monitoring result of the signal generator remains unimpaired by the tooth play (gear play) of gear wheels arranged between the printing unit and the sheet delivery.
According to one development, a further signal generator for position monitoring is arranged in the sheet delivery. The signal generators can be linked to one another, in order to form together a safety device for monitoring the synchronous running of the conveying devices, or a measuring device for monitoring the adjustment of the format of one of the conveying devices. The signal generator and/or the further signal generator can be a rotary encoder and can have a marking and a sensor for detecting the marking. With regard to changing the format, it is advantageous for one of the conveying devices to be mounted displaceably relative to the other one. The machine according to the invention is preferably a printing press.
Other features which are considered as characteristic for the invention are set forth in the appended claims.
Although the invention is illustrated and described herein as embodied in a machine for processing printing material sheets, it is nevertheless not intended to be limited to the details shown, since various modifications and structural changes may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims.
The construction and method of operation of the invention, however, together with additional objects and advantages thereof will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings.